Self-adjusting valve-actuating rod for internal-combustion engines



' Jan. 11,1927.

.w. M. ANDERSON SELF ADJUSTING VALV E ACTUATING ROD FOR INTERNAL COMBUSTI ON ENGINES Filed Feb. 11,

Patented Jan. 11, 1927.

UNITED i STATES WILLIAM M. ANDERSON, OF MINNEAPOLIS, MINNESOTA.

SELF-ADJUSTING VALVE-ACTUATING ROD FOR INTERNAL-COFIBUSTION ENGINES.

Application filed February 11, 1922.

My present invention provides certain improvements in automatic valve actuating rods for internal combustion engines and is in the nature of an improvement on or refinement of the automatic valve-actuating rod disclosed and claimed in my prior Patent 1,443,94cO of February 6, 1923.

In common with the rod of my pending application, my present invention, involves an automatically extensible valve actuating rod or push rod that is entirely mechanical in its operation, that will automatically extend itself to take up play between the cam shaft and valve, that will, under no circumstance, prevent proper seating of the valve, and which, moreover, will automatically compensate for or take care of those changing conditions caused by expansion and contraction when the engine heats up or cools 40 off.

In the accompanying drawings, which illustrate the present invention, like characters indicate like parts throughout the several views.

Referring to the drawings:

Fig. 1 is a vertical section showing one of the improved valve rods applied to an engine of the overhead valve type; a

Fig. 2 is a vertical section taken through 39 the rod approximately on the line 2-2 of Fig. 1;

Fig. 3 is a fragmentary section partly on the line 3-3 of Fig. 2 and with some parts shown in full;

315 Fig. 4 is a transverse section on the line 4- 1 of Fig. 3;

Fig. 5 is a fragmentarysection illustrating a. slightly modified feature of construction which may be involved in the improved rod;

Fig. 6 is a fragmentary side elevation showing several of the rods applied to an engine and illustrating a modified arrangement of the rod-actuating springs; and

Fig. 7 is an enlarged horizontal section on Serial No. 535,740.

lifter spring,'and the cam shaft, all of which parts may be assumed to be those of a well known overhead valve type of engine, such, for example, as found in use in the well known Buick automobile.

The term push rod will be hereinafterv used in a broad sense to include any kind of a valve-actuating rod which, by end movement or thrust or otherwise, will open a valve. The push rod, as herein illustrated, is applied in the customary place between the valve lifter 16 and the rocker arm 15, and it comprises a main rod 21, which, at its lower end, has a head 22 seated in the valve lifter 16 and pressed downward by the spring 19.

Shrunk onto or otherwise rigidly secured to the upper end of the rod 21 is a tubular externally threaded rod extension 23. Working with threaded engagement on the threaded portion of this tubular rod extension 23 is a sleeve 24, the intermediate portion of which is expanded to form an internal cone surface 25, and'the upper portion of which is expanded to afford clearance between the same and the upper portion of the rod extension-23. The expanded upper portion of the sleeve 24; is internally threaded and is engaged by the external threads of a sleeve extension 26 that is adjustably locked to'said sleeve 24 by a lock nut 27. The upper portion of the rod extension 23 is threadless and works telescopically within the sleeve extension 26.

Working slidably through the upper end of the head of the sleeve extension 26 and in the tubular rod extension 23, is a rod section 28 that is' axially aligned with the rod 21 and is axially adjustable in respect thereto. This rod section 28, at its upper end, has a spherical head 29 seated in the outer end of the rocker arm 15 in the usual way. Above the sleeve extension 26, the rodsection 28 has an outstanding stop flange 30 spaced from the opposing upper end or stopping surface of the sleeve extension 26. If desired, a washer 31, of wood fibre or the like, may be placed around the rod 28 in the gap formed between the stop flange 30 and the stop surface of the sleeve extension'26, but this washer should not completely close said gap.

The rod extension 23 has longitudinal slots 32 and the lower end portion of the rod section 28 has a longitudinal slot 33. A flat tapered key or wedge element 34 is placed in the slots 32 and 33 and is engageable with the frictional cone surface 25 of the sleeve 24. The numeral 35 indicates a short plunger placed within an axial seat formed in the rod section 28and extended to form a seat for a small coiled spring 36. This coiled spring 36, acting through the plunger 35, keeps the wedge key 34 seated against the uncut lower end of the rod section 28.

I have found that the action of the rod may be improved by splitting the edge 34 or making the same of a plurality of relatively thin keys of the same shape, placed side by side and having beveled or sharpenededges for action on the conical surface 25 of the sleeve 2-4. These several wedge sections have highly efficient frictional grip on said frictional conical surface but do not interfere with the automatic movements when said wedge is released from said conical surface.

The numeral 37 indicates a coiled torsion spring that surrounds the rod 21, is anchored at its upper end to the lower end of the sleeve 24, and, at its lower end, is anchored to the rod 21, as shown, directly to a collar 38 on said rod, (see Fig. 2). The numeral 39 designates a light tube that surrounds the torsion spring 37, forming a housing there for, and is secured to the lower end of the sleeve 24.

The numeral 40 indicates a light coiled spring placed in the tubular rod extension 23 and compressed between the upper end of the rod 21 and the lower end of the rod section 28. This spring 40 causes the wedge 34 to take up slack the instant any wear, even to the thousandth of an inch, takes place, and without depending on momentum to extend the composite rod in length.

Operation.

In first applying the rod, as shown in Fig. 1, the sleeve extension 26 will be screwed into the sleeve 24 until just the right gap, see Fig. 2, is left between the washer 31 and the striking shoulder 30 of the upper rod section 29, and then the nut 27 is tightened to lock the elements 24 and 26 together. The spring 36 and plunger 35, pressing against the wedge 34, will keep the latter pressed against the lower portion of the slot 33 in the rod extension 23, and the torsion spring 37 will keep the conical surface 25 engaged with the wedge 34. The spring 36 is of sufficient tension to produce enough friction between the wedge and conical surface 25 to lock the sleeve 24 against rotation, but the tension of said spring 36 is not sufficient to overcome the valve spring 14 and, hence, closing of the valve 12 is always insured.

When the cam acts on the rod, the spring 36 will yield, permitting the shoulder 30 to strike the washer 31; (if said washer were not provided, said shoulder 30 would strike the upper end of the sleeve extension 26), and then said rod becomes an unyielding element and will positively open the valve 12 against the tension of its spring 14.

The spring 40 or the equivalent thereof constitutes a highly important feature of my present invention and it insures taking up of the slack independently of momentum imparted to the rod elements under edgewise movements of the rod. The spring 36 reacts aaginst the rod section 28, holds the wedge at the lower extremity of the slot 33 of said rod section 28 and holds the wedge 34 engaged with the conical surface 25 only when said spring 36 is slightly compressed so as to carry the lower portion of said rod section 28 slightly away from the lower edge of said wedge. The normal compression of said spring36 will represent the play provided for expansion and, as already described, may be adjusted, more or less than, say, four one-thousandths of an inch play between the shoulder 30 and washer 31. Whenever wear permits the lower end portion of the rod section 28 to be pressed against the lower edge of the wedge 34, by the spring 40, said spring 40 will release said wedge from the conical surface 25 and then the torsion spring 37 will immediately act to take up the wear but not, however, to destroy the normal gap between the shoulder 30 and washer 31.

In practice, of course, the above described movements will not be considerable in extent, but rather infinitesimal and will take place whenever the slightest wear occurs, so that, in practice, or use, a predetermined gap between the washer 31 and shoulder 30 will always be maintained. This gap does not, therefore, vary as the rod is extended, but may be set for any desired amount of clearance required by adjustment of'the rod extension 26 in respect to the sleeve extension 24.

The purpose of the gap above noted is to prevent interference with seating of the valve due to expansion and contraction. \Vithout the gap, the rodwould be automatically extended, but if the rod should contract with cold, the torsion spring 37 would act to take'up the slack produced and then, when the engine is hot, said rod would b extended or expanded by the increasing temperature and would frequently unseat the valve or, at least, interfere with the tight closing thereof. With the gap, however, whenever expansion of the rod by heat would otherwise tend to unseat the valve, the spring 36 will yield under the greater force of the valve spring 14 and will permit the valve to properly seat. The gap noted may, therefore, be made only sufiicient to take care of expansion and contract. It has now been observed that the wedge 34 will move out of engagement with the conical friction surface 25 and permit the spring 37 to rotate the sleeve'24 only when play between the parts has permitted the rod section 28 to move outward in the sleeve extension 26,

but under all movements produced by expansion and contraction due to varying temperature, the spring 36 keeps the wedge 3a in frictional contact with the surface 25 and prevents rotation of the sleeve 24:.

From the above description given and the statements made, the principals of construction and operation involved in this extensible rod are thought to have been made clear and that it, therefore, becomes obvious that the invention is capable of a large range of modification.

The construction illustrated in Fig. is like that already described except that the torsion spring 37, at its lower end, is' anchored to a sleeve 41 frictionally seated in the lower end of the sleeve 39 and is provided with a knurled flange, by means of which said sleeve may be rotatively adjusted to seat said spring 37 under the desired tension.

The rods illustrated in Figs. 6 and 7 are or may be like the rods above described, except that the rotary sleeves 24 are provided with outstanding flanges 24 having circumferentially spaced perforations, and in lieu of the torsion springs above described, torque-producing coiled springs 42 are diagonally connected to the perforated flanges 24 of adjacent admission and exhaust-controlling rods. Obviously, the tension of the spring 42 or the torque-producing effect thereof in the rods may be varied by adjusting the ends of said spring into different holes of the flanges 245.

What I claim is:

1. An extensible valve actuating rod having cooperating stop surfaces, a yielding device operative to normally maintain a predetermined gap between said stop surfaces, and an automatic device including a releasing spring and operative to take up all play in excess of that of said predetermined gap between stop surfaces.

2. An extensible valve actuating rod having cooperating stop surfaces, a clutch in said extensible rod, a yielding gap-maintaining device operative on said clutch to maintain a predetermined gap between said stop surfaces, a spring operative to release said clutch when the play exceeds that of said gap, and an automatic rod-extending device operative through said clutch to take up all play in excess of that of said predetermined gap.

3. A valve actuating device comprising extensible sections with co-operating stops on said sections, a friction clutch operative to follow up and maintain the extending movement of said rod sections, a yielding element normally maintaining a predetermined gap between the stops of said sections, and a spring operative to release said clutch when the play exceeds that of said predetermined gap.

4. A valve actuating push rod comprising rod sections, the one rod section having a yieldingly pressed wedge and the other rod section having an adjustable sleeve with a clutch surface co-operating with said wedge, and a spring operative to release said clutch when play exceeds a predetermined amount.

5. In an internal combustion engine, the combination with a Valve and a valve-actuating cam, of a cam-operating valve-actuating push rod interposed between said cam and valve and comprising rod-forming elements, a clutch normally holding said rod elements having co-operating gap-forming stop surfaces, a spring incorporated in said push rod normally holding said clutch set and tending to maintain said gap, and a spring operative to release said clutch when the play exceeds that of the predetermined gap between said step surfaces.

6. A valve actuating device comprising extensible sections with co-operating stops on said sections, and a friction clutch operative to follow up and maintain the extending movements of said sections, in further combination with a light spring exerting force constantly tending to release said clutch.

7. A valve actuating push rod comprising two aligned rod sections, the first having a sleeve working with threaded engagement thereon, a spring tending to rotate said sleeve in a direction to extend the length of the rod and said sleeve having a conical internal clutch surface, a wedge co-operating with said conical clutch surface and seated in said second rod section for axial movement, and a spring seated in said second rod section and normally pressing said wedge into contact with said conical clutch surface, in further combination with a light spring exerting force constantly tending to release said wedge.

8. A valve actuating push rod comprising rod sections, the one rod section having a yieldingly pressed wedge and the other rod section having an adjustable sleeve with a clutch surface co-operating with said wedge. said wedge comprising a plurality of dupli cate wedge sections placed flatwise together and operating substantially as a single Wedge.

9. The structure defined in claim 8 in which said wedge sections have beveled sharp edges for direct engagement with the clutch surface of said adjustable sleeve.

In testimony whereof I aflix my signature.

WILLIAM M. ANDERSON. 

